ISSN (E): 2349 – 1183 ISSN (P): 2349 – 9265 3(2): 3 96–407, 2016 Research article Species richness and diversity along the altitudinal gradient in Tungnath, the Himalayan benchmark site of HIMADRI Zubair A. Malik* # and Mohan C. Nautiyal High Altitude Plant Physiology Research Centre (HAPPRC), HNB Garhwal University, Srinagar (Garhwal) Uttarakhand-246174, India #Present address: Sheikh-ul-Aalam Memorial (SAM) Govt. Degree College, Budgam, Jammu & Kashmir-191111, India *Corresponding Author: [email protected] [Accepted: 18 July 2016] Abstract: Alpine ecosystems are likely to show the effects of climate change earlier and more clearly than other ecosystems. The main purpose of the recently launched research initiative, HIMADRI (Himalayan Alpine Dynamics Research Initiative) is the long term monitoring of the ecologically sensitive parameters at benchmark sites selected in various regions of Indian Himalayan Region. The aim of the present study was characterization of one of the HIMADRI benchmark sites (Tungnath, Western Himalaya) and to provide a baseline data about the species richness and diversity along the altitudinal gradient for long monitoring. Four sites were selected along an altitudinal gradient (3200–3600 m asl). A total of 52 plant species belonging to 40 genera and 21 families were reported from the study area during the different seasons of year. Species richness showed a non-significant positive correlation (r=0.53) with altitude but diversity showed a slightly negative correlation (r=-0.05) with it. The reinvestigation of these sites in future (e.g. after a decade or more) will help in understanding the effect of climate change in IHR in terms of changes in species composition and diversity or in terms of species shifts from one vegetation zone or/and ecotone to another. Keywords: Alpine ecosystems - Climate change - Species migration - HIMADRI. [Cite as: Malik ZA & Nautiyal MC (2016) Species richness and diversity along the altitudinal gradient in Tungnath, the Himalayan benchmark site of HIMADRI. Tropical Plant Research 3(2): 396–407] INTRODUCTION Altitude and climate are the two main factors that determine the prominent vegetation zones of the mountains that are the most remarkable land forms on earth surface (Malik 2014). The area of mountains where closed canopy forests end and give way to open vegetation is known as the alpine treeline ecotone. ‘Alpine’ is commonly used in a broad sense for the treeless areas above a low-temperature determined treeline in the high reaches of mountains. The alpines are characterized by scanty rainfall, high wind velocity, low temperature, high intensity of ultraviolet (UV) radiation, blizzards and snow storms (Nautiyal et al. 2004). The plants of this zone show some adaptations to these conditions and are generally dwarfed, stunted, woolly or spiny, and develop a mosaic patch of different forms (Walker et al. 1994). They possess an early growth initiation with a short vegetative span ranging from several days to a few months (Bowman & Damm 2002). The community as a whole usually exhibits seasonal fluctuations and its structure and composition are strongly influenced by the extent to which periodic phenomena in the individuals are adjusted to each other (Kershaw 1973). The distribution of plant species within alpine areas is often regulated by climate or climate-influenced ecological factors. Therefore they are considered particularly sensitive to the influence of predicted climatic change (Pauli et al. 2007). As a result, alpine ecosystems are likely to show the effects of climate change earlier and more clearly than some other ecosystems (Grabherr 2000). Therefore, long term monitoring programs such as the Global Observation Research Initiative in Alpine Environments (GLORIA) have been established worldwide in different continents (www.gloria.ac.at). This program involves recording information about composition of vascular species and soil temperatures according to a common protocol. This protocol can be www.tropicalplantresearch.com 396 Received: 08 April 2016 Published online: 31 August 2016 Malik & Nautiyal (2016) 3(2): 396–407 . used anywhere to examine patterns in species richness and diversity on the mountain peaks along altitudinal gradients and for different aspects (Pauli et al. 2004). Biological diversity includes the richness and evenness (relative abundance) of species amongst and within living organisms and ecological complexes (Polyakov et al. 2008). Knowing the species diversity patterns and the vegetation as a whole is fundamental for conservation of natural areas. Species richness and diversity are the simple and easily interpretable indicators of biological diversity. These are ecologically sensitive parameters. The number of species in a particular plant community varies markedly along the altitudinal range of its growth, which depends on a set of complex factors that characterize the habitat of individual species (Malik et al. 2014). Slobodkin & Sanders (1969) opine that community is a function of severity, variability and predictability of the environment in which it develops. Therefore, diversity tends to increase as the environment becomes more favourable and more predictable (Putman 1994).The factors such as soil nutrient content, slope, aspect and altitude have been shown to exert an important control on species richness and diversity on a great variety of ecosystems (Kharakwal et al. 2005). The Indian Himalayan Region (IHR) occupies a special place in the mountain ecosystems of the world. Himalayas, world’s youngest mountains with diverse vegetation are important locations for research into ecology and biodiversity conservation (Pei 2001). But remoteness, difficult terrain, lack of resources and poor infrastructure are some inherent difficulties that hamper the extent and quality of research in the region (Negi et al. 2014). Thus there is a need for urgent attention from all concerned. Keeping in view all the aforesaid facts, recently a multi-site research initiative, HIMADRI (Himalayan Alpine Dynamics Research Initiative) has been launched that works on the protocol of GLORIA. This program, like GLORIA, involves recording information about composition of vascular species and soil temperatures in the alpine regions of IHR. The aim of the present study is to characterize the HIMADRI benchmark site (Tungnath) of Uttarakhand state of IHR on the basis of species richness and diversity of plants along an altitudinal gradient. MATERIALS AND METHODS a) Study Area The study area is being carried out in Tungnath area (N 30°29'–30°30' and E 79°12'–79°13') of Western Himalaya, India. Tungnath forms a part of Kedarnath Wildlife Sanctuary (Fig. 1). It lies in the upper catchment of the Alaknanda and the Mandakini Rivers, two major tributaries of the Ganges. Figure 1. Map showing the location of study area (Tungnath). www.tropicalplantresearch.com 397 Malik & Nautiyal (2016) 3(2): 396–407 . Geology, soil and climate The rocks around Tungnath are mainly mylonitized gneisses, augen gneisses, schists and granites constituting munsiari formation (Agarwala 1973). The weathering bedrocks, that provide the bulk of the loose material in these mountains, are crystalline and metamorphic; with sedimentary deposits of Paleozoic age (Gupta 1964). The soil texture is sandy loam, light grey to brown in colour and acidic in nature with a pH range between 4 and 5 (Rai et al. 2012a). Meadows with deep soil cover are seen in northern aspects, while the southern faces generally have large rock spurs and crevices and are either barren or have a few lithophytes. Four distinct seasons are observed in the study area viz., short summer (May–June), Monsoon (July–mid September) and autumn (mid-September–October) and long winter (November–April). The snow cover lasts for about 4–5 months and melts during April–May that marks the arrival of favourable conditions for plant growth. The growth period lasts for about 5–7 months only. Mean Annual temperature at the timberline ecotone (3300 m) ranged between -8.91 (January) and +25.6°C (May) with an average of 6.65±0.68°C. Mean temperature of the warmest month was 12.56±1.23°C, in July (Fig. 2). Annual precipitation was 2410.5±432.2 mm, of which 89.5%, recorded during June–September (Adhikari et al. 2011). Figure 2. Mean air temperature, rainfall and snowfall at timberline ecotone in the study area during 2008- 2010 (Courtesy: Raiet al. 2012a). Forest types and vegetation According to Champion and Seth's (1968) classification the study area falls in sub-alpine forest and alpine scrubs. The description of the vegetation types of the area is as under: Sub-alpine forest: The sub alpine forest is formed by Abies spp., Betula utilis, Quercus semecarpifolia, Acer spp., Sorbus sp. etc. Shrub layer is represented by Rhododendron campanulatum, R. barbatum, Viburnum spp., Rosa sericea, Rubus niveus, Salix sp. etc. Herb layer is represented Trachydium roylei, Rumex nepalensis, Persicaria wallichii, Thamnocalamus spathiflorus etc. Timberline ecotone: Timberline in the study area ranges between 3250–3350 m which is formed by Betula utilis and Abies spectabilis in the north to north-west facing slopes, while south to south west facing slopes dominated by Q. semecarpifolia and R. arboreum (Rai et al. 2012b). In the steep rocky slopes timberline is dominated by climatically modified dwarf and stunted individuals of R. arboreum, which grow very slowly in harsh climatic conditions. Other major shrub species in this zone are Lonicera spp., Rubus niveus,